Machine for grinding lenses



March 2 1926.

M. BENTZON MACHINE FOR GRINDING LENSES Filed July 5, 1921 3 Sheets-Sheet l March 2 1926.

M. BENTZON v MACHINE FOR GRINDING LENSES Filed July 5, 1921 3 Sheets-Sheet 2 W 057 gm? Q March 2 1926.

, 1,575,311 M. BENTZON MACHINE FOR GRINDING LENSES- Filed July 5, 1921 3 Sheets-Sheet 3 Fig. J.

asta M0122, 1926.

MAI-COLE BENT-Z011, NEUILLY-SUB-SEINE,

' mcnmn roa eam'nrne Lenses. I

Appiication filed July 5,

To all whom it may concern: 7

Be it known" that I, MALCOLM BnN'rzoN, a subject of the King of Denmark, residing at 41 Avenue de Neuilly, Neuilly-sur-Seme, Paris, France, have invented new and useful Improvements in Machines for G rinding Lenses, of which the following is a specification.

My invention relates to machines ifor grinding bi-local lenses, and is esp'ecially designed for smoothing and pol1shing, although it can also be used for roughlng purposes. H

In the specification of my former British Patent No. 18,109, of 1910, there i described a machine for grinding plano lei-focallenses, such machine consisting of a rotating lens-holder in combination with a series of grinding discs which are carried on .spindles mounted in a stationary head and driven by flexible shafts. present invention is to adapt a machine of this type to the grinding of convex and concave lens surfaces, for example, for meniscus and cylindrical lenses.

According to the invention each of the grinding discs is carried by a holder mounted on a radially disposed arm, which is pivoted to the stationary head so that its angle can be adjusted in a vertical plane. The adjustment can be controlled in any convenient way, say, by the use of a vernier scale or by the employment of standard templates or gauges. Furthermore, the grinding disc holder can be adjusted longitudinally in the arrnwhich carries it, this being effected, for example, by means of an adjusting screw, for the purpose of enabling the position of the grinding disc to be varied in the radial direction.

As will be understood, the grinding discs are rotated through the medium of flexible shafts, and these flexible shafts are advantageously carried between pairs of guide plates or the like.

In conjunction with the grinding discs, ll may also employ a central stop which is fixed in the stationary head, and against which the centre of the lens surface to be ground is caused to contact, when the machine is set for grinding.

The main object of the,

19 1: Serial No. 482,438.

To enable the invention to be fully understood, I will describe it by reference to the accompanying drawings, in which Figure 1 is a sectional elevation of a machine for grinding bi-tocal lenses, constructed in accordance with the invention.

Figure 2 is ahorizontal section on the line 22, Figure 1, but showing the parts in a diflerent position. to

Figure 3 is a sectional view similar to the right hand portion of Figure lbut showing the parts in the same position as in Figure 2.

Figure 4 is a View showing another position of some of the parts. v

Figure 5 is a view of a detaildrawn to, a smaller scale than the rest of the figures.

llhe frame of the machine advantageously comprises a base a and a head 6, the latter being supported on the said base by four I pillars 0 and a pillar d,.the pillars a being equi-distant from the vertical centre of the machine and from one another,'whilst the pillar d is arranged intermediate ottwo oi the pillars 0. e is the holder mounted on the spindle 7 for supporting the lens A being treated, the axis of which holder is coincident with the vertical centre of the machine. This spindle is carried in bearings g on the bracket 7 which latter is adjustable vertically on the pillar d to which it can be clamped by a set-screw 2". lfhe spindle also passes through a bearing j on the base a, which'bearing also serves as a pivot or bearing for a pulley 70 designed to 35 rotate the said spindle through the medium of the key 1 (see Figure 5-) which engages an extended keyway in the spindle f to allow of the vertical movement of the latter when the bracket his adjusted on the pillar d.

m indicates the grinding discs and n the holders carrying. each of the said discs through the medium of the shafts m which are pressed upon by springs m to impart pressure to the said discs in the usual way. 0 indicates the arms carrying the holders n which .arms. are arranged radially with re' spect to' the axis of rotation of the lensholder e, and p are the pivots on the said arms whereby the latter are pivoted to the head?) so that their angle in the vertical plans can be adjusted, the said pivots being in the form of trunnion pins enga ing bearin'gs 9 supported by pillars 1- depending from the head 6. The outer ends of the arms 0 work in conjunction with graduated scales 0 on curved portions 8 of the head 7) and to which. portions they can be clamped by screws t passing through slots in the said curved parts 8. The said arms may be provided with Vernier scales 0 at their ends, as shown in Figure 1, to enable very fine angular adjustments of the arms 0 to be made. Instead of the scales 0 on the portions 8 of the head 6, standard templates or gauges may be provided for determining the angular positions of the arms 0.

The holders 92 carrying the guiding discs m are arranged to slide in the arms 0 to all0\\L of their longitudinal adjustment relatively thereto, the said arms being provided with V-grooves n with which the correspondingly shaped sides of the holders engage. This adjustment is conveniently effected by screws u carried in bearings on the arms and engaging fixed nuts 1) on the holders.

'w indicates the flexible shafts for driving the shafts m of the grindin discs m, the said shafts w being connected to vertical shafts w located in hearings in the pillars 0 and carrying at their lower ends spur pinions w gearing with a common spur-wheel integral with, or secured to, the pulley k. t wil thus be seen that the pulley serves for rotatin both the lens-holder e and the grinding discs m.

2 is the central stop which is fixed to the head 6 and against which the center of the surface of the lens A is caused to contact when the machine is set for grinding, as indicated in Figures 1 and 3.

In Figure 1 it will be seen that the arms 0 are inclined so that they can grind or polish the convex surface of a lens A whilst in Figure 4 they are inclined so that they can grind or polish a lens having a concave surface. .Figure 3 shows the arms 0 in position for grinding or polishing a 'flat surface.

Claim:

A lens grindin machine of the kind hereinbefore referre to, comprising a lens holder, a plurality of grinding discs de signed to act upon one only of the two lens surfaces, means whereby each grinding disc can be presented to the lens at the angle required to grind or polish convex or concave surfaces thereon and a stop to contact with the centre of the lens to determine the grinding position therefor.

MALCOLM BENTZON. 

